Windows DHCP Database Cleanup Interval on Windows Server 2019

[Paolo Maffezzoli]

Hi everyone,

On Windows Server 2019 with DHCP role, a specific scope has few IP addresses available. There are some IP addresses expired but not released due the grace period.

The question, anyone knows what is the default time for DHCP database cleanup for expired IP addresses ?

[Leos Marek]

Not sure how you mean it. There is just lease time in the scope properties. Once the Ip pass the lease time and dont renew, its free for reuse.

[Paolo Maffezzoli]

I remember on Windows Srv 2008R2  60 minutes was the default before the clean up and release of IP addresses expired. The default grace period was 4 hours.

[Leos Marek]

not sure how you mean it. There is just the lease time. If the IP was taken at 9:00 and my lease time is 1 hour, its released ad 10:00 and can be used by another device. No grace period.

[Paolo Maffezzoli]

There was a grace period on db clean for dhcp running on Windows Server 2003R2 and 2008R2.

“Although reducing the lease duration creates more DHCP-related network traffic, it increases the rate at which addresses are returned to the available address pool for reassignment. With an average volume of DHCP request traffic, Windows Server 2003 DHCP has a four-hour default grace period after which an expired lease can be reused. This means that an address is marked for deletion four hours after the lease expires, regardless of lease duration. When the volume of DHCP-related traffic is heavy and no leases are available to service lease requests, DHCP immediately instantiates a cleanup cycle, which reclaims any leases marked for deletion. By default, the cleanup cycle occurs every 60 minutes. ”

ok, now it is no longer used and it is no longer necessary to change the default time.

 

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